A micro-architectured material as a pressure vessel for green mobility

A shellular is a micro-architectured material, composed of a continuous smooth-curved thin shell in the form of a triply periodic minimal surface. Thanks to the unique geometry, a shellular can support external load by co-planar stresses, unlike microlattice, nanolattice, and mechanical metamaterial. That is, the shellular is the only stretching-dominated material with the highest strength at a density of less than 10^-2g/cc. Therefore, it is expected to support internal pressure, too, by the bi-axial tensile stresses like a balloon. For more than 300 years, spherical and cylindrical vessels have been viable yet compromised options for storing pressurized gases. However, emerging green mobility necessitates a safer and more spatially conformable storage solution for hydrogen than spherical and cylindrical vessels these conventional vessels. In this study, we propose to use the shellular as a pressure vessel. Due to the distinct topological nature - periodic micro-cells constituting the triply periodic minimal surface, the alternative pressure vessel can be tailored individually for spatial requirements while ensuring safety with leak-before-break. For a given constituent material and prescribed pressure, the achievable internal volume-per-total weight of a P-surfaced, cold-stretched, double-chambered shellular vessel with a number of cells more than 15 × 15 × 15 can exceed the practical upper bound of both spherical and cylindrical vessels. For the applications, a thin shell with the large surface area of this micro-architecture is ideal for interfacial transfer of heat or mass between its two sub-volumes under internal pressure.